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Showing posts with label Ransom note. Show all posts

SFile (Escal) Ransomware Modified for Linux Attacks

 

The SFile ransomware, also known as Escal, has been ported to work and encrypt data on Linux-based operating systems by its developers. 

Attacks with this new Linux edition were discovered late last year, according to a report published last week by Chinese security firm Rising, which was substantiated by The Record with MalwareHunterTeam, one of the developers of the ID-Ransomware project. 

In February 2020, the SFile (Escal) ransomware was first observed in assaults. The first versions were exclusively designed to encrypt Windows systems. The ransomware has been deployed in targeted assaults against corporate and government networks for the previous two years. 

SFile is typically used in these attacks to encrypt data and leave a ransom note instructing victims to contact the attackers via one of three emails and negotiate a ransom for the decryption key. 

A SFile Linux variation was discovered late last year, following a typical trend in the ransomware ecosystem where groups have developed Linux versions of their payloads, with an encryption strategy identical to its original Windows variant but with a few modifications. 

The option to encrypt data depending on a time range, according to MalwareHunterTeam, was the most intriguing of these—as a way to encrypt current files, which may be more important for some victims and are often not included in recent backups. However, the SFile ransomware is one of the few instances where the victim's name appears in the extension appended to each encrypted file. 

Several Chinese firms were among the most recent victims of SFile assaults. According to the Rising report, one of these victims was Chinese IT business Nuctech, which was sanctioned by the US in late 2020 for giving air travel passenger information to the Chinese government—the company's name was identified in encrypted files in a sample discovered by Rising researchers. 

Despite the presence of a Linux variant, the number of SFile attacks is still limited in comparison to the operation of more well-known ransomware families like Conti, LockBit, Grief, and STOP.

Night Sky: New Ransomware Targeting Corporate Networks

 

The new year has brought with it new ransomware named 'Night Sky,' which targets corporate networks and steals data in double-extortion attacks. 

The Night Sky operation began on December 27th, according to MalwareHunterTeam, which was the first to identify the new ransomware. The ransomware has since published the data of two victims. 

One of the victims got an initial ransom demand of $800,000 in exchange for a decryptor and the promise that the stolen material would not be made public. 

How Night Sky encrypts devices

A sample of the Night Sky ransomware seen by BleepingComputer has a personalised ransom note and hardcoded login credentials to access the victim's negotiation page. 

When the ransomware is activated, it encrypts all files except those with the.dll or.exe file extensions. The ransomware will not encrypt the following files or folders: 
AppData
Boot
Windows
Windows.old
Tor Browser
Internet Explorer
Google
Opera
Opera Software
Mozilla
Mozilla Firefox
$Recycle.Bin
ProgramData
All Users
autorun.inf
boot.ini
bootfont.bin
bootsect.bak
bootmgr
bootmgr.efi
bootmgfw.efi
desktop.ini
iconcache.db
ntldr
ntuser.dat
ntuser.dat.log
ntuser.ini
thumbs.db
Program Files
Program Files (x86)
#recycle

Night Sky appends the.nightsky extension to encrypted file names while encrypting them. A ransom letter named NightSkyReadMe.hta is included in each folder, and it provides details about what was stolen, contact emails, and hardcoded passwords to the victim's negotiation page. 

Instead of communicating with victims through a Tor site, Night Sky employs email addresses and a transparent website that runs Rocket.Chat. The credentials are used to access the Rocket.Chat URL specified in the ransom note. 

Double extortion tactic: 

Before encrypting devices on the network, ransomware operations frequently grab unencrypted data from victims. Threat actors then utilize the stolen data in a "double-extortion" scheme, threatening to leak the information unless a ransom is paid. 

Night Sky built a Tor data leak site to leak the data of victims, which now contains two victims, one from Bangladesh and the other from Japan. While there hasn't been much activity with the new Night Sky ransomware operation, one should keep a watch on it as we enter the new year.